Giovanni Visconti, the former Italian road race champion, has undergone surgery on his right tibia after the Movistar rider suffered a nasty crash at the People's Choice Classic in Adelaide on Sunday.

The 50-kilometre criterium that acts as the prelude to the Tour Down Under - the UCI WorldTour curtain-raiser - was won by Giant-Shimano's Marcel Kittel after the German outsprinted compatriot André Greipel of Lotto-Belisol in the South Australia capital.

The race, though, was overshadowed by Visconti's crash on the seventh of 25 laps of the street circuit in downtown Adelaide.

While Visconti was forced to withdraw immediately following the crash, Team Sky's Chris Sutton sustained a fractured wrist after being caught up in the incident though the Aussie rider still managed to complete the race in fourth place.

"It’s a massive blow not to be continuing on with the lads because they did an incredible job for me last night," Sutton later said. "My groin and my knee were pretty sore in the race but it was only afterwards, on the way back to the hotel, that my wrist started hurting and I couldn’t grip the handlebars.

"I’m trying to stay upbeat and looking forward to the Tour of Qatar now. That should be my first race back and I’ll have a week or so on the turbo before getting myself back on the road.

"In the meantime, I’ll be staying within the team during the Tour Down Under an cheering the lads on."

Nathan Earle will replace Sutton with the Tasmanian making his WorldTour debut after joining the British outfit

"We couldn’t have wished for anyone better to come in," Sutton said of the rider who supported Richie Porte in the Australian National Road Championships earlier this month. "He showed at the Nationals he’s riding really well and good on him for coming into the group at such short notice.

Meanwhile, Tuesday's opening stage of the Tour Down Under will go ahead as planned, its race director said on Monday, after forest fires had put the race in danger.

The Tour said it was taking advice from the Country Fire Service and South Australian Police and decided to go ahead with the stage based on their advice.

"Obviously this advice might change subject to the conditions and we'll continue to be guided by the advice we receive from the Country Fire Service and South Australian Police," race director Mike Turtur said in a statement.

"But our advice is that the race route and the towns through which the race will travel are not in the fire area and it is safe for us to continue as planned."

Fires in the Barossa Valley have threatened lives and destroyed properties as extreme heat and high winds fanned dozens of bushfires across Australia.

It also nearly led to the Tour's first potential stage cancellation or course change since its 1999 inception.

"Our thoughts are with the people affected by the fires but we urge cycling fans to help them through this by supporting the local economies of the region," said Turtur.

"Spending money in the shops and restaurants will help in the recovery for the area."